Vincent Martin
Université Blaise-Pascal, F- Clermont-Ferrand, UFR STAPS, Faculty Member
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This study aimed to evaluate the metabolic responses during a whole-body strength training (WBST) session and to test the effects of a 8-week WBST program on metabolic adaptations and body composition. Oxygen consumption ( ), and the rate... more
This study aimed to evaluate the metabolic responses during a whole-body strength training (WBST) session and to test the effects of a 8-week WBST program on metabolic adaptations and body composition. Oxygen consumption ( ), and the rate of lipid oxydation (LipOx) were measured during both WBST and walking incremental exercises. Metabolic responses during walking, body composition, and anthropometric characteristics were measured before and after the WBST training period. was similar during a WBST session performed at 80% of MVC (15.4 ± 3.9 ml/min/kg), and during walking at 4.5 km/h (16.8 ± 2.0 ml/min/kg). During walking at 4.5 km/h, LipOx did not differ before (0.47 ± 0.20 g/min) and after training (0.43 ± 0.11 g/min), while was significantly reduced (-7.2 ± 10.4 %; p<0.01) after the WBST program. Waist circumference, supra-iliac skinfold thickness, and body fat percentage were also significantly (p<0.001, p<0.01and p<0.01 respectively) reduced after training. This stu...
Neuromuscular fatigue of the knee extensor (KE) and plantar flexor (PF) muscles was characterized after a 65-km ultramarathon race in nine well-trained runners by stimulating the femoral and tibial nerves, respectively. One week before... more
Neuromuscular fatigue of the knee extensor (KE) and plantar flexor (PF) muscles was characterized after a 65-km ultramarathon race in nine well-trained runners by stimulating the femoral and tibial nerves, respectively. One week before and immediately after the ultramarathon, maximal twitches were elicited from the relaxed KE and PF. Electrically evoked superimposed twitches of the KE were also elicited during maximal voluntary contractions (MVCs) to determine maximal voluntary activation. MVC and maximal voluntary activation decreased significantly after the ultramarathon (-30.2 +/- 18.0% and -27.7 +/- 13.0%, respectively; P < 0.001). Surprisingly, peak twitch increased after the ultramarathon from 15.8 +/- 6.3 to 19.7 +/- 3.3 N. m for PF (P < 0.01) and from 131.9 +/- 21.2 to 157.1 +/- 35.9 N for KE (P < 0.05). Also, shorter contraction and half-relaxation times were observed for both muscles. The compound muscle action potentials (M wave) were not significantly altered by...
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The aim of this study was to characterize neuromuscular fatigue in knee extensor muscles after a marathon skiing race (mean +/- SD duration = 159.7 +/- 17.9 min). During the 2 days preceding the event and immediately after, maximal... more
The aim of this study was to characterize neuromuscular fatigue in knee extensor muscles after a marathon skiing race (mean +/- SD duration = 159.7 +/- 17.9 min). During the 2 days preceding the event and immediately after, maximal percutaneous electrical stimulations (single twitch, 0.5-s tetanus at 20 and 80 Hz) were applied to the femoral nerve of 11 trained skiers. Superimposed twitches were also delivered during maximal voluntary contraction (MVC) to determine maximal voluntary activation (% VA). EMG was recorded from the vastus lateralis muscle. MVC decreased with fatigue from 171.7 +/- 33.7 to 157.3 +/- 35.2 Nm (-8.4%; p < 0.005) while % VA did not change significantly. The RMS measured during MVC and peak-to-peak amplitude of the compound muscle action potential (PPA) from the vastus lateralis decreased with fatigue by about 30% (p < 0.01), but RMS.PPA-1 was similar before and after the ski marathon. Peak tetanus tension at 20 Hz and 80 Hz (P(0)20 and P(0)80, respectiv...
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The well-established central deficit in ultraendurance running races is not understood. The use of transcranial magnetic stimulation (TMS) in parallel with peripheral nerve stimulation provides insight into the source of these central... more
The well-established central deficit in ultraendurance running races is not understood. The use of transcranial magnetic stimulation (TMS) in parallel with peripheral nerve stimulation provides insight into the source of these central changes. The aims of this study were to determine the presence and magnitude of voluntary activation deficits, especially supraspinal deficits, after a mountain trail-running race and to determine whether this can be explained by simultaneous changes in corticospinal excitability and intracortical inhibition. Neuromuscular function (TMS and femoral nerve electrical stimulation) of the knee extensors was evaluated before and after a 110-km ultratrail in 25 experienced ultraendurance trail runners during maximal and submaximal voluntary contractions and in relaxed muscle. Voluntary activation assessed by both femoral nerve electrical stimulation (-26%) and TMS (-16%) decreased and were correlated (P < 0.01). Decreases in potentiated twitch and doublet...
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The aim of this study was to compare the use of transcutaneous vs. motor nerve stimulation in the evaluation of low-frequency fatigue. Nine female and eleven male subjects, all physically active, performed a 30-min downhill run on a... more
The aim of this study was to compare the use of transcutaneous vs. motor nerve stimulation in the evaluation of low-frequency fatigue. Nine female and eleven male subjects, all physically active, performed a 30-min downhill run on a motorized treadmill. Knee extensor muscle contractile characteristics were measured before, immediately after (Post), and 30 min after the fatiguing exercise (Post30) by using single twitches and 0.5-s tetani at 20 Hz (P20) and 80 Hz (P80). The P20-to-P80 ratio was calculated. Electrical stimulations were randomly applied either maximally to the femoral nerve or via large surface electrodes (ES) at an intensity sufficient to evoke 50% of maximal voluntary contraction (MVC) during a 80-Hz tetanus. Voluntary activation level was also determined during isometric MVC by the twitch-interpolation technique. Knee extensor MVC and voluntary activation level decreased at all points in time postexercise ( P < 0.001). P20 and P80 displayed significant time × gen...
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We tested the influence of string stiffness on the occurrence of forearm muscle fatigue during a tennis match. Sixteen tennis players performed two prolonged simulated tennis matches with low-stiffness or high-stiffness string. Before and... more
We tested the influence of string stiffness on the occurrence of forearm muscle fatigue during a tennis match. Sixteen tennis players performed two prolonged simulated tennis matches with low-stiffness or high-stiffness string. Before and immediately after exercise, muscle fatigability was evaluated on the forearm muscles during a maximal intermittent gripping task. Groundstroke ball speeds and the profile of acceleration of the racquet frame at collision were recorded during each match. The peak-to-peak amplitude of acceleration and the resonant frequency of the frame were significantly greater with high- (5060 ± 1892 m/s2 and 204 ± 29 Hz, respectively) than with low-stiffness string (4704 ± 1671 m/s2 and 191 ± 16 Hz, respectively). The maximal and the averaged gripping forces developed during the gripping task were significantly reduced after the tennis match with high- (−15 ± 14%, and −22 ± 14%, respectively), but not with low-stiffness string. The decrease of ball speed during t...
Research Interests: Mechanical Engineering, Biomedical Engineering, Tennis, Humans, Female, and 12 moreMale, Young Adult, Mechanical Stress, Skeletal Muscle, Muscle Fatigue, Elastic Modulus, Athletic performance, Sports Equipment, Equipment Design, Tissue Mechanics (Applied Biomechanics), Forearm, and physical exertion
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Introduction. It has been shown that the ability to produce maximal strength with respect to muscle size is lower in children than in young adults. That difference may be attributed to the lower ability of children to fully activate their... more
Introduction. It has been shown that the ability to produce maximal strength with respect to muscle size is lower in children than in young adults. That difference may be attributed to the lower ability of children to fully activate their motor units (O’Brien et al. 2009). However, other studies reported comparable levels of voluntary activation (VA) in children and older subjects (Belanger and McComas, 1989). Part of these controversies could be attributed to discrepancies in the mechanical conditions of muscle contraction, i.e. muscle length. Therefore, the aim of the present study was to compare the effect of muscle length on the level of VA at short and long muscle lengths between children and adults. Methods. Thirteen prepubertal boys (10.2 ± 1.1 y) and ten men (23.9 ± 2.9 y) performed isometric 5-s maximal voluntary contractions (MVC) of the knee extensor (KE) muscles at three muscular angles (20°, 90°, 100°; 0° = full extension) interspersed with at least 60-s passive recover...
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The aim of the present study was to compare the effect of muscle length on the level of voluntary activation (VA) at short and long muscle lengths between children and adults. Thirteen prepubertal boys (10.2 ± 1.1 y) and ten men (23.9 ±... more
The aim of the present study was to compare the effect of muscle length on the level of voluntary activation (VA) at short and long muscle lengths between children and adults. Thirteen prepubertal boys (10.2 ± 1.1 y) and ten men (23.9 ± 2.9 y) performed 5-s maximal isometric voluntary contractions (MVC) of the knee extensor muscles at three muscular angles (20°, 90°, 100°; 0° = full extension) interspersed with at least 60-s passive recovery periods. Single magnetic stimulations were delivered to the femoral nerve during MVCs to determine the level of VA by means of the twitch interpolation technique. The specific torque was calculated as the absolute torque divided by thigh muscle mass, as assessed using DXA. Finally, the theoretical specific torque that could be produced with a complete (i.e. 100%) activation level (specific torque@100%VA) was estimated from the values of specific torque and VA. Results showed a higher specific torque in adults at 90° and 100° but not at 20°. Acco...
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Tennis tournaments often involve playing several consecutive matches interspersed with short periods of recovery. The objective of this study was firstly to assess the impact of several successive tennis matches on the physical... more
Tennis tournaments often involve playing several consecutive matches interspersed with short periods of recovery. The objective of this study was firstly to assess the impact of several successive tennis matches on the physical performance of competitive players and secondly to evaluate the potential of sports drinks to minimize the fatigue induced by repeated matches. This was a crossover, randomized controlled study. Eight male regionally-ranked tennis players participated in this study. Players underwent a series of physical tests to assess their strength, speed, power and endurance following the completion of three tennis matches each of two hours duration played over three consecutive half-days (1.5 day period for each condition). In the first condition the players consumed a sports drink before, during and after each match; in the second, they drank an identical volume of placebo water. The results obtained were compared with the third 'rest' condition in which the sub...
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Research Interests: Perception, Running, Muscle strength, Biological Sciences, Humans, and 18 moreApplied, Male, Central Nervous System, Applied Physiology, Electromyography, Middle Aged, Adult, Time Factors, Muscle Fatigue, Muscle contraction, Biological markers, Volition, Torque, Action Potentials, Lower Extremity, Biomechanical Phenomena, Physical Endurance, and Tibial nerve
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The aim of this study was to examine the effects of fatigue induced by a 65-km ultramarathon on the oxygen cost of running (Cr) and cycling (Ccycl). The day before and immediately after the race, a group of nine well-trained male subjects... more
The aim of this study was to examine the effects of fatigue induced by a 65-km ultramarathon on the oxygen cost of running (Cr) and cycling (Ccycl). The day before and immediately after the race, a group of nine well-trained male subjects performed two submaximal 4-min exercise bouts: one cycling at a power corresponding to 1.5 W x kg(-1) body mass on an electromagnetically braked ergometer, and one running at 11 km x h(-1) on a flat asphalt roadway. Before oxygen cost determinations, the subjects performed 12 &amp;amp;quot;ankle&amp;amp;quot; jumps at a given frequency that was fixed by an electronic metronome (2.5 Hz). From the non-fatigued to the fatigued condition, there was a significant increase in minute ventilation for both running (P &amp;amp;lt; 0.01) and cycling (P &amp;amp;lt; 0.0001). Significant changes were also found in respiratory exchange ratio both for running (P = 0.01) and cycling (P &amp;amp;lt; 0.0001). However, running and cycling differed in that Cycyc increased significantly by [mean (SD)] 24.2 (11.5)% (P &amp;amp;lt; 0.001), suggesting an alteration of muscle efficiency, while Cr did not change with fatigue [186.8 (14.1) mlO2 x kg(-1) x km(-1) vs 186.8 (18.7) mlO2 x kg(-1) x km(-1)]. In addition, contact times during hopping increased significantly from 0.173 (0.019) ms to 0.194 (0.027) ms (P &amp;amp;lt; 0.01). Analysis of the factors that determine Cr indicate that the subjects modified their movement pattern in order to decrease the mechanical cost of running in such long-term fatigue conditions.